Paul further extended, ornamented, and fortified Forchtenstein Castle with architect Domenico Carlone.[11] At Forchtenstein Castle, Paul founded the Esterházy family's treasure house and created an extensive portrait gallery of Esterházy family ancestors.[11]

Paul shortly after his elevation to Count Esterházy of Galántha by Elias Widemann.

Paul was married twice.[1][2] He married first to his niece[1] Countess Orsolya Esterházy of Galántha, daughter of his brother Count István Esterházy of Galántha and his wife Countess Erzsébet Thurzó of Bethlenfalva, on 7 February 1652 in Eisenstadt.[1] Paul's marriage to his eldest brother's daughter was done in part to prevent the division of the Esterházy family's property[2] Paul and Orsolya had nineteen children:[1]

After the death of his first wife, Paul married Countess Éva Thököly of Késmárk, daughter of István, Count Thököly of Késmárk and his wife Mária Gyulaffy of Rátót.[1] Paul and Éva had the following children:[1]

Paul died in Eisenstadt on 26 March 1713.[1][2][3] To secure his fortune, Paul founded the Austrian model of the fee tail and settled his successor in his will through the establishment of two primogeniture lines for his sons Michael and Joseph.[2] In his will, Paul left his sons Michael and Joseph two estates which were meant to remain separate, but were rejoined under Joseph's ownership in 1721.[2][3]